The Company of Biologists

Table 2.

The effects of a bolus injection of CO₂-enriched water into the buccal cavity on plasma catecholamine levels in rainbow trout(Oncorhynchus mykiss)

	Intact fish					Extirpated fish
	[NA]	[A]	Total concentration	[NA]	[A]	Total concentration
Pre-CO₂	3.8±2.2	6.7±0.8	10.5±1.9	1.2±0.3	6.4±0.9	7.8±1.2
External CO₂	9.0±6.0	9.6±1.0	18.6±6.2^*	2.5±1.2	10.7±2.3	14.2±3.2^*

	Intact fish					Extirpated fish
	[NA]	[A]	Total concentration	[NA]	[A]	Total concentration
Pre-CO₂	3.8±2.2	6.7±0.8	10.5±1.9	1.2±0.3	6.4±0.9	7.8±1.2
External CO₂	9.0±6.0	9.6±1.0	18.6±6.2^*	2.5±1.2	10.7±2.3	14.2±3.2^*

A, adrenaline; NA, noradrenaline.

Data shown are means ± 1 S.E.M. (N=7); an asterisk indicates a significant difference from the pre-CO₂ value.